Command Triggers (v17)

Hi,

Please find attached the newest revision of the command trigger patch,
rebased against tonight's master as about just now, with more docs, the
new argument passing infrastructure (same as classic triggers with magic
variables, including support for plpgsql, pltcl, plperl and plpython),
and the pseudo time renamed to “command_trigger” per Tom's request.

This version also fires ANY trigger and specific triggers from the same
place, you have access to just the same information in both cases.

In the PL support code, I'd like to have some opinion about the NULL
handling I've put in (and well, the rest too), in a quick search it
looks like what other places are doing but I'm (re)discovering two
programming languages here, not talking about their implementation as a
PostgreSQL embedded PL (it certainly feels like it took me more time to
find out how to spell out the pl code in TCL and perl than to edit the C
support code for them).

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support